1. Field of the Invention
The present invention relates to an electrodeionization apparatus and, more particularly, to an electrodeionization apparatus having an endblock formed of a resilient material.
2. Description of Related Art
Electrodeionization (EDI) is a process that may be used to purify water by removing ionizable species from liquids using electrically active media and an electrical potential to influence ion transport. The electrically active media may function to alternately collect and discharge ionizable species, or to facilitate the transport of ions continuously by ionic or electronic substitution mechanisms. EDI devices can include media having permanent or temporary charge and can be operated to cause electrochemical reactions designed to achieve or enhance performance. These devices also include electrically active membranes such as semi-permeable ion exchange or bipolar membranes.
Continuous electrodeionization (CEDI) is a process wherein the primary sizing parameter is the transport through the media, not the ionic capacity of the media. A typical CEDI device includes alternating cation-selective membranes and anion-selective membranes. The spaces between the membranes are configured to create liquid flow compartments with inlets and outlets. A transverse DC electrical field is imposed by an external power source using electrodes at the bounds of the membranes and compartments. These electrodes are typically supported by rigid endblocks formed of an inert material and a housing and/or endplates. Electrodeionization devices have been described by, for example, Giuffrida et al. in U.S. Pat. Nos. 4,632,745, 4,925,541 and 5,211,823, by Ganzi in U.S. Pat. No. 5,259,936, by Ganzi et al. U.S. Pat. No. 5,316,637, by Oren et al. in U.S. Pat. No. 5,154,809 and by Kedem in U.S. Pat. No. 5,240,579, which are incorporated herein by reference.
The present invention is directed to an electrodeionization apparatus having at lease one end block formed of a resilient material.
In another embodiment, the electrodeionization apparatus comprises an ion-depleting compartment, an ion-concentrating compartment, and an endblock having a first surface adjacent an electrode and a second surface adjacent an endplate. The endblock is formed of a resilient material.
In another embodiment, the electrodeionization apparatus comprises at least one endplate encased in a resilient material.